1. Alt is no long for object/part delection
2. Alt is defined to select part in View3D
Signed-off-by: yifan.wu <yifan.wu@bambulab.com>
Change-Id: If0f14f79a321be2d0320a841e15dc973715364ea
(cherry picked from commit 9c092f2d20b89470202df037180425b2ecb8ef82)